Metal Matrix Composites

The comparative analysis of the two hybrid composites, obtained by the compocasting process, based on A356 and ZA-27 alloys and reinforced with 10 wt. % SiC and 0, 1 and 3 wt. % graphite (Gr) is presented. Optimisation of their tribological behaviour was performed by the Taguchi method and the artificial neural network (ANN). Tribological tests were performed on a block-on-disk tribometer, at three sliding speeds, three normal loads and a sliding distance of 600 m, without lubrication. Results obtained by the ANOVA showed that the hybrid composites based on A356 alloy have the better wear resistance and that the composite reinforced with 10 wt. % SiC and 1 wt. % Gr has the lowest wear rate. The lowest coefficient of friction was obtained for a composite based on ZA-27 alloy reinforced with 10 wt. % SiC, at a normal load of 10 N and sliding speed of 1 m/s.

The investigation is focused on the wear behaviour at elevated test temperature of composite Ni-P/SiC deposit, with varying concentration of the reinforcing SiC particles. The phase evolution measured by X-ray diffraction suggests slight crystallisation during wear testing at 200 °C. In coating without reinforcing particles, adhesive wear is accompanied by microcracks. The thermal heat generated and the cyclic loading could have induced subsurface microcracks. Owing to the effective matrix-ceramics system in composite coatings, fine grooves, abrasive polishing and uniform wearing are observed. Reinforcing particles in the matrix hinder microcrack formation and significantly reduce the wear rate. Triboxidation is confirmed from energy dispersive X-ray spectrometry.

Aluminum oxide (oxide Al₂O₃), or alumina, is one of the most critical and widely used ceramic oxides in high temperature mechanical applications. This is due to its reliable mechanical properties, thermal stability, and chemical resistance. Alumina has various polymorphs and transition sequences from the metastable polytypes of γ, δ, θ, and κ to the stable α-phase
can lead to a defining step in application performance.

In this study, hybrid composites of Al7075 reinforced with boron carbide (B4C), titanium (Ti), and
graphite (Gr) were synthesized using the stir casting technique and was investigated to assess their
suitability for aerospace applications. Six different compositions were prepared by varying the vol% of
B4C and Ti and maintaining a constant vol% of graphite in all composites. The physical andstructural
characteristics were analyzed through density measurements, porosity evaluation, and x-ray
diffraction (XRD) analysis. The experimental and theoretical density values showed a decreasing trend
with increased reinforcement, Porosity values were found to decrease with higher Ti content. XRD
confirmed the presence of Al matrix phases along with B4C, Ti, and graphite, , indicating uniform
distribution and phase stability. Corrosion resistance was assessed using static immersion tests,
polarization studies, Nyquist plots, and Bode plots. The base alloy demonstrated susceptibility to
galvanic corrosion, with minimal passivation. Composites with boron carbide showed moderate
corrosion rate (−1.479 mm y−1), and those with titanium exhibited remarkable improvements
(−1.116 mm y−1). The polarization curves of the reinforced composites displayed lower current
densities in the anodic region with an Ecorr and Icorr value of 776.856 mV and 8.332 mA for composite
reinforced with boron carbide and 727.265 mV and 8.001 mA for composites reinforced with
titanium, indicating enhanced passivation and reduced corrosion rates. Nyquist plots revealed larger
semicircular arcs for titanium-reinforced composites, signifying higher charge transfer resistance
(Rct). Among the tested compositions, the hybrid composite with 7 vol% Ti, 3 vol% B4C, and 2 vol%
Gr exhibited improved passivation, and superior corrosion resistance.

This study focuses on investigating the effects of process parameters, namely, Peak current (Ip), Pulse on time (Ton), Pulse off time (Toff), Water pressure (Wp), Wire feed rate (Wf), Wire tension (Wt), Servo voltage (Sv) and Servo feed setting (Sfs), on the Material Removal Rate (MRR) and Surface Roughness (SR) for Wire electrical discharge machining (Wire-EDM) of nickel using Taguchi method. Response Surface Methodology (RSM) is adopted to evolve mathematical relationships between the wire cutting process parameters and the output variables of the weld joint to determine the welding input parameters that lead to the desired optimal wire cutting quality. Besides, using response surface plots, the interaction effects of process parameters on the responses are analyzed and discussed. The statistical software Mini-tab is used to establish the design and to obtain the regression equations. The developed mathematical models are tested by analysis-of-variance (ANOVA) method to check their appropriateness and suitability. Finally, a comparison is made between measured and calculated results, which are in good agreement. This indicates that the developed models can predict the responses accurately and precisely within the limits of cutting parameter being used.

Today, due to its lightness and superior properties, the use of Aluminum (Al) materials has increased considerably. In the production of Powder Metal (PM) or nanomaterials, it is possible to form the materials required by the additives to be added into the main composition. When recent studies investigated, it has been seen that the Graphene NanoPlate (GNP) additive improves the mechanical properties of almost all materials. In this review study, the properties of GNP added to Aluminum PM and Nanomaterials are investigated. Also, the mechanical properties of Al-GNP materials sintered with different methods such as hot pressing, hot extrusion, and plasma sintering are investigated and compared among themselves.

The increasing demand for lightweight material specifications has forced researchers to develop lightweight materials that are inexpensive, can be produced on a large scale, and are environmentally friendly. One solution that has been developed is an aluminum composite reinforced with sea sand. Indonesia has the second longest coastline in the world, which means that the country is rich in maritime resources, one of which is sea sand. The ceramic contents of SiO2, SiC, and Al2O3 allow sea sand to be used as a reinforcement in aluminum composites for engineering purposes. The most effective manufacturing method of AA6061-sea sand composites is stir casting, but the homogeneity and distribution of particles are the main disadvantages of the stir casting method. Various factors affect particle distribution and homogeneity, one of which is the flow during the stirring process. The increase in turbulent flow in the stirring process affects the homogeneity and distribution of the particles. One way to create a turbulent flow when stirring is to add baffles. This paper examines the effect of adding baffles during the stir casting process on the mechanical properties of AA6061-sea sand composites. The mechanical properties of AA6061-sea sand composites were characterized using the Brinell hardness test according to ASTM E-10. The test results show that the addition of baffles during the stir casting process decreases the hardness of the AA6061-sea sand composites due to the turbulent flow that occurs. This makes the material more porous, which makes the AA6061-sea sand composites less hard.

Discover the strength, durability, and applications of Aluminium Bronze Rods in this educational guide. Learn about their composition, properties, manufacturing process, and industrial uses across marine, aerospace, and heavy engineering sectors.

Many of the engineers and researchers have done their research on composite materials and they found that the composite which are made from two different materials with different chemical and physical property that, when combined ,produce a material with characteristics different from individual components .Both artificial and natural fibers will be used for the preparation of samples. The samples will be made from epoxy, bamboo, flax, glass fibers by using hand layup method. Then tribological test of the material will be done by using those samples by using pin on disc apparatus. From the outcome the following result will be calculated i.e wear rate, coefficient of friction, volume loss, frictional force, surface roughness.

Nickel-based superalloy, particularly Inconel 718, is a promising candidate in advanced structural and hightemperature applications, including turbine blades, combustors, and turbochargers. However, high-efficiency energy systems such as jet engines and land-based gas turbines demand increasingly high strength for advanced structural applications. Therefore, significant efforts are underway to enhance the strength of these materials. Reinforcement of graphene nanoplatelet (GNP), owing to its exceptional mechanical strength, lightweight, high aspect ratio, and high level of coherency with metal matrix, has been proposed as an effective way of incorporating high strength into the existing Inconel 718. In addition, the spark plasma-assisted heating process is an emanating technique for fusing materials within a short duration and at a lower temperature. Thus, diffusion bonding of composites based on GNP dispersion in IN718 has been processed via the spark plasma sintering (SPS) technique. This study presents a systematic approach for probing the effect of GNP fraction on the microstructure and mechanical properties of Inconel 718. The composites were prepared with varying fractions of GNP (i.e., 0.1-0.5 wt%) at optimized processing parameters using high-energy ball milling followed by spark plasma sintering. Microstructural characterization and evaluation of mechanical properties of SPS-assisted samples were performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Vickers indentation, and uniaxial tensile testing. The IN718-0.5 GNP sample showed a ~29 % increase in hardness, ~64 % in yield strength, ~8 % in tensile strength, and ~18 % elongation to fracture, achieving an excellent strength-ductility balance compared to pure IN718. The remarkable increase in mechanical properties of the IN718 is attributed to grain refinement, dislocation strengthening, solid-solution strengthening, and Orowan strengthening. Transmission electron microscopy (TEM) results indicated that NbxTiyC (~Nb 1.5 Ti 0.5 C type precipitates) formed at the interface of the grain boundary after embedding GNPs in the IN718 matrix, resulting in increasing strength of the materials.

Deformation of ductile crystalline-amorphous nanolaminates is not well understood due to the complex interplay of interface mechanics, shear banding, and deformation-driven chemical mixing. Here we present indentation experiments on 10 nm nanocrystalline Cu-100 nm amorphous CuZr model multilayers to study these mechanisms down to the atomic scale. By using correlative atom probe tomography and transmission electron microscopy we find that crystallographic slip bands in the Cu layers coincide with noncrystallographic shear bands in the amorphous CuZr layers. Dislocations from the crystalline layers drag Cu atoms across the interface into the CuZr layers. Also, crystalline Cu blocks are sheared into the CuZr layers. In these sheared and thus Cu enriched zones the initially amorphous CuZr layer is rendered into an amorphous plus crystalline nanocomposite.

In the present work, copper metal matrix composites (CuMMCs) were developed using the electric resistance sintering (ERS) technique. Micro-particles of silica sand (5 wt%) and graphene nanopowder (0.1, 0.2, & 0.3 wt%) were added as reinforcement in the copper (Cu) matrix. Green compacts were pre-sintered at 600 • C in a tubular furnace containing N 2 gas, then finally sintered through resistance heating and conduction heating simultaneously in high-density graphite die by applying a plain direct current (200-400 A) of low voltage (3-5 V). Characterizing the hybrid composites by X-ray diffraction, energy dispersion spectroscopy, scanning electron microscopy (SEM), and Raman spectroscopy showed the presence of Cu, sand, and graphene nanopowder. A uniform dispersion of the reinforcement particles was found in the prepared composites. Further, the incorporation of 0.2 wt% graphene with a sintering temperature of 900 • C resulted in the maximum relative sintered density (RD) and hardness (RH) of 6.98 g/cm 3 and 73 HRB with a minimum wear rate (WR) of 0.00550 mg/s, respectively. In addition, the average coefficient of friction (COF) was found to be 0.44 for the composite having 0.3 wt% graphene. The RSM predicted optimum values of 7.216 g/cm 3 , 68.989 HRB, and 0.006 mg/s for RD, RH, and WR, corresponding to the 0.144 wt% graphene and 900 • C sintering temperature. The % error between the experimental and predicted RD, RH, and WR values was found to be 1.409 %, 1.950 %, and 3.01 %, respectively. Moreover, the SD values for the three output values were 0.270, 0.475, and 1.514, respectively.

In the present scenario, research on Thermal Barrier Coatings (TBCs) is attracting significant attention in hightemperature applications due to the rising demand in industrial applications, such as gas turbine blades and internal combustion engine components. To meet these demands, it is essential to enhance the mechanical and oxidation properties of thermal barrier coatings. The atmospheric plasma spray methodology for producing these coatings has become a central focus in recent times. In this work, TBCs were prepared by blending pure alumina and Yttria-Stabilized Zirconia (YSZ) in equal proportions. Extensive study of TBCs carried out under hightemperature conditions through thermal cycle tests at elevated temperatures, around 850 • C. A total of 350 thermal cycles were conducted, and microstructures of the coating surface were examined at 150, 250, and 350 cycles. High-temperature stress, generated due to the sintering of the coating, also influences the life of the coatings. Specimen with a topcoat thickness of 300 μm, exhibited good thermal shock resistance compared to the specimens with topcoats of thickness of 100 μm and 200 μm. The effects of process parameters, porosity, and thermal shock resistance are presented in detail. The topcoat with a thickness of 300 μm demonstrated excellent thermal shock resistance and reduced formation of thermally grown oxide (TGO). The porosity of the coating, found to be between 2% and 3%, contributed to its dense nature, effectively reducing oxidation rates and enhancing the coating's lifespan under cyclic high-temperature conditions.

Compression studies on three-dimensional foam-like graphene and h-BN (3D-C and 3D-BN) revealed their high cross-plane thermal conductivity (62 - 86 Wm(-1)K(-1)) and excellent surface conformity, characteristics essential for thermal management needs. Comparative studies to state-of-the-art materials and other materials currently under research for heat dissipation revealed 3D-foam's improved performance (20 - 30% improved cooling, temperature decrease by ΔT of 44 - 24°C).

Impact events involving laminate composites had been largely studied through computational approaches, due to mainly to the technical difficulties and high costs associated with experimental tests, and the availability of highly sophisticated computational codes. The impact constraints are active only on the contact / target interface, so energy conservation is enforced only for contact elements. The underlying finite elements defining the interior of impacting bodies do not satisfy energy conservation. In the present work, high velocity impact event of 'dummy bird' against balanced Epoxy_Carbon_UD laminate composite structure was simulated through AUTODYNE explicit finite element package. Smoothed particle hydrodynamics (SPH) techniques is adopted to describe the motion of the impacted composite plate and the soft body projectile, with different porosities. The obtained energy and momentum variations with time from different porosities of two bird models are compared and results were plotted.

1,2Assistant Professor, Department of Industrial and Production Engineering, Institute of Technology Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur, Chhattisgarh, India, 495009 3Assistant Professor, Department of Mechanical Engineering, National Institute of Science and Technology, Berhampur, Odisha, India, 761008 4Professor, Department of Industrial and Production Engineering, Institute of Technology Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur, Chhattisgarh, India, 495009 -----------------------------------------------------------------------***-------------------------------------------------------------------Abstract This review paper is broadly focused on the effect of the different ceramic particulates (SiC, B4C and Al2O3) on the mechanical properties of the Al and Al alloy. Ceramic Particulate Reinforced Aluminium Metal Matrix Composites (PRAMMCs) provide improved properties i.e. improved hardness, improved strength to weight ratio, tensile &...

Graphene possesses excellent properties such as, high Young's modulus (1 TPa), high fracture strength (~125 GPa) and extreme thermal conductivity (~5000 W/m/K), therefore, can serve as an ideal reinforcement material for the metal based High Tech structural nanocomposites. In the present work, a novel chemical synthesis method has been adopted for the in-situ synthesis of aluminium-graphene (Al-Gr) nanocomposite powders with varying compositions using graphene oxide (GO) as the precursor. The pure aluminium powder was initially cryomilled to refine the crystallite size. Subsequently, Al-reduced graphene (Al-Gr) nanocomposite powders were synthesized employing different volume proportions of GO (referred as 0.5, 2, 4, and 6 ml) dispersed in deionized water. The synthesized nanocomposite powders were ball milled followed by consolidation using spark plasma sintering under the optimized conditions. The nanocomposite powder as well as SPSed samples were characterized using X-ray diffraction (XRD), Raman Spectroscopy and electron microscopy. Scanning electron microscopy (SEM) studies of nanocomposite powders have depicted wrinkled structure typical of reduced graphene. Raman spectra have shown regular D, G, 2D and D+G bands and a modulated 2D peak having intensity significantly less than the G peak was observed for the nanocomposite powders confirming multilayered graphene is synthesized. The graphene wrinkles were determined in the size of 100 nm or more. Microhardness of SPS sintered nanocomposites is found progressively increased with the increasing content of reduced graphene with up to 58% improvement over pure Al was observed for the maximized GO content depicting potential for energy efficient high strength applications. The synthesized Al-graphene nanocomposites are novel in terms of an innovative, indigenously developed and scalable to bulk synthesis approach based on in-situ chemical synthesis route adopted.

Polymeric nanocomposites are an emerging research topic, as they improve fiber-reinforced composites’ thermo-mechanical and tribological properties. Nanomaterials improve electrical and thermal conductivity and provide excellent wear and friction resistance to the polymer matrix material. In this research work, a systematic study was carried out to examine the tensile and hardness properties of a carbon fiber epoxy composite comprising nano-sized Al2O3 and SiC fillers. The study confirms that adding nano-fillers produces superior tensile and hardness properties for carbon fiber-reinforced polymer composites. The amount of filler loading ranged from 1, 1.5, 1.75, and 2% by weight of the resin for Al2O3 and 1, 1.25, 1.5, and 2% for SiC fillers. The maximum tensile strength gain of 29.54% and modulus gain of 2.42% were noted for Al2O3 filled composite at 1.75 wt.% filler loading. Likewise, enhanced strength gain of 25.75% and 1.17% in modulus gain was obtained for SiC-filled composite ...

Composites are very significant materials for a large variety of applications in various engineering areas because of their enhanced mechanical, physical, and machining properties. These materials have been endless of applications because of their behavior, mainly mechanical, compared to other materials since it has demonstrated less density and significantly higher resistance. The composite materials have many benefits and excellent properties in comparison to conventional materials, which make the application of composites in many areas. More research and studies are being carried out to improve the characteristics and manufacturing techniques further, to promote the potential implementation of composites. In recent years, the application and development of MMCs have increased in many engineering fields. With the arrival of innovative technologies, high research activities and the development of different processing techniques, composites with improved properties become attractive materials for engineering applications. A wide array of metals, especially low-density metals or alloys, are generally selected as the matrix material for the composite. This research article provides a brief overview of matrix materials generally used in composites, and types of composites, with their important aspects.

In the Present work cenosphere dispersed aluminium matrix composites were fabricated by powder metallurgy route. The friction and wear behaviour of these composites were studied by using a pin on disc machine. Various weight percentages of cenospheres (10, 20, & 30 wt. %) were reinforced with pure aluminium. The results showed that density decreases with addition of cenospheres but hardness increases with addition of cenosphere particles. The dry sliding wear mechanism was also established and presented in detail. The sliding wear test shows a significant improvement in wear resistance of pure aluminium with addition of cenosphere particles. SEM studies were also carried out to know the wear surface morphology of the products.

In this study, the effect of heat treatment on the tribologic al properties of Al-Cu-Mg alloy reinforced with 4 wt.% SiC particles with 650 nm average particle size has been investigated. The age hardening proce ss consists of solution treatment at 540 °C for 6 h, followed by water quenching and ageing at different temperature s of 175, 200 and 225 °C with soaking times of 3, 6 and 9 h. Hardness measurements were applied to monitor the precipitation effect and the aged samples were then subjected to wear tests under dry sliding condit ions against steel and alumina counterfaces. The results showed that the reinforced material exhibits an enhanced agei ng response compared to the unreinforced material in the same heat treatment conditions. The rate of ageing increases with increasing temperature; however, ageing at 200 and 225 °C for more than 6 h resulted in over-ageing. The best combinations for the enhanced tribological properties for the composite material were selected as 6 h ageing at 225 °C. The precipitation effect for this alloy can be enhanced by the small addition of SiC nanoparticles. Having a small amount of nanoSiC particles with fine precipitates inside the matrix further increases the hardness and wear properties.

In the present work, 6061Al-TiB2 composites were synthesized using two types of base 6061Al powder (prealloyed and premixed) through powder metallurgy route. Dry sliding wear test was performed on the specimens using pin on disk apparatus to investigate the effect of TiB2 content on tribological characteristics. The microstructure, worn surface, and subsurface were also characterized using scanning electron microscope to examine the wear mechanism of prealloyed- and premixed-based composites. A mathematical model was developed using parameters (composition and applied load) to predict wear rate and correlated with experimental results. Adequacy of developed model has been validated using analysis of variance. Results indicated that premixed 6061Al-TiB2 composites have superior tribological properties as compared to the prealloyed 6061Al-TiB2 composite.

nium Metals, LLC -Nanocarbon has been successfully incorporated in molten metals and metal alloys using a new method of manufacturing in which the molten metal (or metal alloy) acts as ionizing medium causing nanocarbon structures to form in-situ. C in concentrations up to ∼10% weight was incorporated in Ag, Al and Cu. The bonding between the carbon and the metal is very strong and persists after re-melting and resolidification. These materials, called "covetics," show improved properties over those of the host metal. For example, the thermal conductivity of Cu covetic is higher than pure Cu. The electrical conductivity of Al covetic is higher than for pure Al. The yield strength of Al and Cu covetics is higher than the pure metals. We have used X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy to investigate the incorporation of C in the metal. Scanning and transmission electron microscopy (TEM) were also employed along with energy dispersive X-ray spectroscopy and electron energy loss spectroscopy (EELS). The nanocarbons in the covetics are in the form of, graphene nanoribbons, and amorphous nanocarbon, and all are bonded to the metal. The C-K edge in the EELS, and the Raman spectra from these samples show signals characteristic of graphitic sp2 bonding.

Composite materials have been used to replace many conventional materials because of high mechanical strength and lighter weight since several decades. In general, scientists are preparing metal matrix composites with 1 additive at different weight ratios. However, comparison of the effect of different reinforcements such as nano alumina (n-Al2O3) and graphene with metal casting is not studied before. In this paper, Al-7.0 Si-0.3Mg aluminum alloy known as A356 was used as matrix material and different fractions of n-Al2O3 (0.5, 1.0 and 1.5 wt. %) and graphene (0.075, 0.15 and 0.25 wt. %) were used as reinforcements. The novel hybrid stirring (mechanical and ultrasonic) was applied to produce samples with homogeneous distribution of additives and all the samples were subjected T6 heat treatment. Uniaxial tensile test was applied to determine the mechanical properties and quality index (QI) was calculated by using these results. The results showed that higher yield strength (YS) and ultimate tensile strength (UTS) values were obtained with 0.5 wt.% Al2O3 addition and with 0.25 wt.% graphene addition when compared to the reference sample. In comparison to the reference sample, UTS values increased 8.5% and 5.0% with adding n-Al2O3 and graphene, respectively. Likewise, QI values also increased as nearly 20.0% and 13.9% with adding n-Al2O3 and graphene, respectively.

Cu-30 Zn (wt%) alloy is widely used for cartridge case. As received hot rolled (HR) cartridge brass is rolled about 15%, 30%, 40%, and 50% by plane strain rolling at normal room temperature in laboratory. The quantitative microstructure details such as mean grain size and grain size distribution are characterized by optical microscope equipped with microstructure analysis software. The developments of deformation texture are measured by X-ray texture Goniometer and analysis of texture details is done by LaboTex-Edu texture analysis software. The mean grain size is increased with rolling in rolling direction. The grain size distribution shows higher frequency for larger grains with deformation by rolling. The initial stages of rolling produce bi-modal grain size distribution. Later it shifts to multi-modality. The deformation strengthens Bs, L, R, Goss, Taylor, Cu and S texture components. Though the Cu texture orientation shows an increasing trend, the strength of Cu orientation is much less than that of Bs and S components. The transition of texture for Cu, S and Bs texture components is not found in this study.

The primary objective of the present investigation is to examine the mechanical characteristics of hybrid metal matrix composites with an Aluminium base, which are made via the stir casting method. The aim of this this review article is to explore the knowledge on the effects of integrating hybrid reinforcements such as Al2O3, SiC, B4C, TiB2, graphite, fly ash etc on mechanical properties of the hybrid aluminium metal matrix produced through stir casting route. Based on various literature survey, the stir casting processing method has demonstrated its capability to create hybrid AMMC with consistent characteristics. Ceramic particle addition to AMMCs is essential to reach the required strength, hardness, and toughness for these materials. Moreover, within the realm of literature, it is stressed that using industrial and agricultural wastes, such as fly ash, coconut shell ash, and rice husk ash, can promote the sustainable practices without sacrificing its mechanical qualities. The usage of light materials has been shown to decrease the overall stiffness of some composites. Emerging research indicates a likely shift toward aluminum-based hybrid composites as a replacement for ceramic-reinforced composites. This transition is driven by several factors, including their cost-effectiveness, abundant availability, and support for sustainable manufacturing processes. These advantages allow for the creation of hybrid AMMC with mechanical properties comparable to those of conventional particulate-reinforced metal matrix composites.

Due to their mechanical properties, WC-based cermet coatings are extensively used in wear-resistant applications. These coatings are usually produced using thermal spray processes. However, due to the nature and the environment of these spraying processes, the feedstock powder structure and properties suffer from decomposition, which subsequently degrade the performance of the coatings produced. The cold gas dynamic spraying process appears to be a promising alternative technique to preserve the properties of the feedstock powder during the coating preparation. Although the latter technique can minimize or eliminate the degradation of the sprayed material, the deposition of cermet using this technique is a difficult task. In this study, two types of cermet powders, the nanocrystalline (WC-15Co) and the conventional (WC-10Co4Cr) powders were deposited using the cold gas dynamic spraying and the pulsed gas dynamic spraying processes. The feedstock powders and coatings microstructures were investigated by OM, SEM and XRD, as well as their hardness. The results revealed the possibility of depositing cermet coatings onto aluminum substrates using both processes without any degradation of the carbide phase of the feedstock powder. The cold gas dynamic spraying process experienced difficulty in depositing and building up dense coatings without major defects. The pulsed gas dynamic process produced thick cermet (conventional and nanocrystalline) coatings with low porosity as long as the feedstock powder was preheated above 573 K.

The nanocomposite based on carbon nanotubes/aluminum (CNT/Al) was one-step prepared by the DC arc discharge method under an argon/acetone mixed atmosphere. Synthesis was performed by arc plasma on a pure graphite rod, filled by aluminum powder as an anode and aluminum plate as a cathode. Discharge conditions of 85 A and 20 V were used at a pressure range of 375 to 750 Torr. The CNT/Al was characterized by Scanning Electron Microscopy with Energy Dispersive Spectroscopy; Transmission Electron Microscopy; Laser Diffraction Particle Size Analysis; X-Ray Diffraction; Raman Spectroscopy; Thermogravimetric Analysis; and, its reinforcement effect of the CNTs on the aluminum matrix was measured by Vickers microhardness test. This nanocomposite shows agglomerates of multiwalled carbon nanotubes filled with Al 4 C 3 and blended with aluminum particles; moreover, in the nanocomposites was found a hardness increase of 40% for nanocomposites with 1.0 wt.% of CNT/Al.

Nanostructured materials are becoming of major significance, and their investigations require a comprehensive approach. Depending on the size of the smallest feature, the interaction of light with structured materials can be very different. The chapter identifies the nanostructures unique properties that make the nanostructure for varying applications and detailed about the properties.

Al matrix composite reinforced by hexagonal boron nitride (h-BN) with nearly full densification was successfully fabricated by the semi-solid powder metallurgy technique. The h-BN/Al composites were synthesized with elemental pure Al powder size of d 50 ¼ 35, 12 and 2 μm. The powder morphology and the structural characteristics of the composites were analyzed using X-ray diffraction, scanning and transmission electron microscopy. The density, Brinell hardness and compressive behavior of the samples were characterized. Density measurement of the Al composites revealed that the composite densification can be effectively promoted by plenty of embedded liquid phase under pressure. Composites prepared using Al powder with varying granularity showed different grain characteristics, and in situ recrystallization occurred inside the original grains with 35 μm Al powder. A sharp interface consisting of Al/Al 2 O 3 /h-BN was present in the composites. Both the compressive strength and the fracture strain of the investigated composites increased with the decrease of the Al powder size, along with the Brinell hardness. The composite with 2 μm Al powder exhibited the highest relative density (99.3%), Brinell harness (HB 128), compressive strength (763 MPa) and fracture strain (0.299).

This present study is centered on the corrosion behaviors and structural integrity of high strength aluminum‐alloy 7075‐T651 hybridized with carbonaceous coconut shell ash (CSA) and α+β titanium alloy powder in ratio of 50 : 50, fabricated during friction stir processing (FSP). The study examined the base metal – AA7075‐T651 as well as the friction stir processed AA7075‐T651 as control experiments. The Processing parameters used were plunge depth of 0.3 mm, travel speed of 20 mm/min, the tilt angle of 3° and rotational speed of 1500 min−1. The corrosion characteristics were examined with the Potentiodynamic Polarization method in 3.5 % NaCl medium while crystalline phases were studied with x‐ray diffraction (XRD). Results show that fabricated aluminum hybrid composite (AHC) AA7075‐T651/coconut shell ash (CSA)/titanium‐alloy has the highest percentage of inhibition performance efficiency (IPE) of 84.81 % resulting to 0.76938 mm/year corrosion rate and 356.51 Ω polarization resistance...

Aluminium metal matrix and hybrid composites (AMMHCs) are new materials used in recent time that have the capacity to meet the demand of advancement in processing applications. Several types of reinforcement have been used since the inception of friction stir processing (FSP). The most widely used reinforcing material is inorganic (metallic) powders such as silicon carbide, titanium alloy, graphene, iron , stainless steel, nitrides, oxides etc and fewer works have been reported on organic powders (i.e. bioprocessing using agro-wastes powders) such as fly ash, palm kernel shell ash, coconut shell ash, rice husk ash etc. Many researchers have established the roles of reinforcements in the modification of surface and texture of the reinforced metal matrix or hybrid composite material and how it enhanced the mechanical and metallurgical properties of the materials via intense, localized plastic deformation compare to the base material. FSP has advantages over other manufacturing processes in a way that it reduces defects and distortions in the material. FSP alters the physical properties of the base material without altering its physical state, this helps engineers develop attributes such as "high-state-rate superplasticity". The grain refinement occurs on the parent material which improves the properties of the first material while mixing with the second material (reinforcement). Subsequently, allows a variety of properties to be altered and this, in turn, improves its surface modification. The survey is aimed at reviewing different combination and diversified reinforcement particulates employed in the processing of composites of aluminium metal matrix and hybrid and how it enhanced the chemical, mechanical and metallurgical efficacy of the materials. It is very much needed to have a consolidated information about the different reinforcement phases, preparation of the microchannel (groove) that accommodates the reinforcements, its dimensions and various tools geometry that have been used in the past demonstrating the optimum processing results.

This research aims to improve and substantiate the efficiency of homogenization heat-stabilizing Joule heating on ceramic-matrix composites of TiB2-TiC system with a 2:1 component ratio during its synthesis. For this purpose, an improved technological approach is proposed, which is based on the known method of SHS-compacting but differs by the possibility of controlled Joule influence on the synthesis products, which is achieved by the use of a special electrothermal vacuum press-mold functioning according to a particular control algorithm. The task of controlled Joule heating is a compensation of the temperature gradient formed in the synthesized workpiece, which is solved by passing in it a direct current directed in line with the vector of propagation of the combustion wave. An indicator of assessment of the degree of compensation of the noted temperature gradient is the Seebeck effect, excited between the upper and lower surface of the SHS workpiece, which should be brought to zero in the process of Joule thermostatting. It was experimentally revealed that compensation of the noted temperature gradient with heat released predominantly by electrically conductive and Joule-heated TiC grains leads to their softening, which contributes to more uniform compaction of the workpiece due to diffusion coalescence of these grains around prism-shaped hard TiB2 crystals. Such consolidation leads to a significant increase in the quality of structural packaging and a reduction in the number and volume of micropores, as a result of which the performance properties of the composite improve on average by 10-15 %.

Functionally gradient materials (FGMs) were prepared by mixing 5 layers comprised of different ratios of (YSZ-20 %Al2O3) and 422 stainless (SUS422) powders, followed by hot pressing for densification. Two design concepts were proposed: One was a FGM with a monotonic change of the CTE (coefficient of thermal expansion) for each layer, and is designated as the monotonic mode, and the other was a FGM with a change of CTE that is not monotonic for each layer, and is termed the non-monotonic mode. The FGM with a monotonic CTE mode cracked at the ceramic surface after it was removed from the hot pressing furnace. In contrast, the FGM with a non-monotonic CTE mode survived after hot pressing. Based on ABAQUS simulation results, a non-monotonic change in CTE resulted in a decrease of residual stress on the ceramic side but an increase inside the metal-rich layers of the FGMs. The induced change in the stress distribution inside the FGMs was compromised by the deformation of the metal-rich ingredient (SUS422) in the FGM. Thermal shock tests of FGMs were performed between 25 o C and 600 o C. The non-monotonic FGM endured up to 100 thermal cycles with only slight bending, and was free of delamination and cracking. The use of composition-adjusted layers to manipulate thermal expansion coefficients of each layer greatly changed the stress contour of the FGM. It is noted that a modified functional-gradient FGM can be fabricated with a hard ceramic surface on one side to resist high temperature, and a ductile metallic surface on the other side to provide toughness.

Friction and wear in composites containing 50 vol pct granular or flake graphite in 2014 aluminum alloy have been measured for different normal loads and sliding velocities ranging from 25 to 100 N and 0.5 to 3 m/s, respectively. The coefficients of friction and wear are significantly lower in the composites, as compared to those in the matrix alloy containing no graphite. The transition to severe wear takes place at a higher load and sliding velocity as compared to the base alloys, particularly in composites containing granular graphite. In composites containing flake graphite, friction and wear depend on sliding direction relative to the orientation of the flake. This behavior has been explained on the basis of subsurface deformation, leading to transfer of graphite to the tribosurfaces, and the plastic flow of constituent alloy, resulting in covering of the embedded graphite by the matrix alloy.

One dimensional heat transfer during solidification of aluminum melt, with and without alumina particles, has been investigated by the finite difference technique. The results indicate that in the region surrounding the particle, the temperatures are higher as compared with those in absence of particles. The solidification front slows down considerably in the vicinity of alumina particles. A larger particle is more effective in slowing down the solidification front than a small particle or a cluster of two smaller particles of the same total length. The slowing down of the solidification front may be responsible for the observation that the alloy around the ceramic dispersoids is the last fraction to freeze.

Development of metal matrix composites has extended the choice of materials particularly for the space, aero-space and automobile industries, with a view to reduce fuel consumption and operating cost by weight saving. Tailoring of a composite to suit a given application requires choice of constituents and promotion of desirable interfaces. Solidification processing of composites demands particular attention to wetting of dispersoids by alloys, defects like porosities and evolution of microstructures particularly in respect of changing the nature of interfaces in a composite.

Porous ceramics are nowadays recognized to have the potential to be used for a wide variety of industrial applications. These span from filtration in metals foundry and casting to absorption, catalysts and catalyst supports to lightweight structural components. Thus, considerable research efforts are focused on innovative processing technologies resulting in better control of their structures and improvement of their properties. Ceramic foams are within these materials of great interest, especially for their application as filters for aluminum alloys and other nonferrous materials in foundry, in particular because of their resistance to high temperatures. However, shaping such kind of ceramic foams can result difficult and costly. This paper presents an explorative experimental campaign on the workability and characterization of various ceramic foams for the previous mentioned industrial application. grinding and drilling strategies have been applied in order to verify the possibility to effectively process the materials under investigation.

Porous ceramics are nowadays recognized to have the potential to be used for a wide variety of industrial applications. These span from filtration in metals foundry and casting to absorption, catalysts and catalyst supports to lightweight structural components. Thus, considerable research efforts are focused on innovative processing technologies resulting in better control of their structures and improvement of their properties. Ceramic foams are within these materials of great interest, especially for their application as filters for aluminum alloys and other nonferrous materials in foundry, in particular because of their resistance to high temperatures. However, shaping such kind of ceramic foams can result difficult and costly. This paper presents an explorative experimental campaign on the workability and characterization of various ceramic foams for the previous mentioned industrial application. grinding and drilling strategies have been applied in order to verify the possibility to effectively process the materials under investigation.

Polymeric nanocomposites have received substantial interest in recent years because of their diverse potential applications in various fields such as electronics, agriculture, aerospace, automotive, and health care due to their excellent mechanical, electrical, thermal, and barrier properties. However, there is a lack of a comprehensive review focusing on the synthesis methods, properties, and applications of polymeric nanocomposites reinforced with metallic nanoparticles. Hence, this review paper provides a comprehensive understanding of synthesis methods, properties, and emerging applications of these nanocomposites reinforced with metallic nanoparticles. The motivation for this review stems from the growing interest in developing highperformance nanocomposites with tailored properties and enhanced functionality. This paper further addresses the need for a consolidated resource that summarizes the latest developments and highlights future directions in the field of polymeric nanocomposites reinforced with metallic nanoparticles. Finally, the paper concluded the impact of metallic nanoparticles on nanocomposites' properties and their potential applications in sensors, energy storage devices, electromagnetic interference shielding, and biomedical fields. We highlighted the advantages and challenges of these applications and provided a comprehensive understanding of synthesis methods, properties, and emerging applications. This review will further serve as a valuable resource for researchers, engineers, and industry professionals interested in the development and utilization of polymeric nanocomposites reinforced with metallic nanoparticles.

This overview begins by considering the mature situation for polymer matrix composites (PMCs). After a further short section devoted to ceramic matrix composites (CMCs), the main text is devoted to the variety of routes available for processing metallic matrix composites (MMCs). These are divided into those where the main steps are performed in the solid state and those where the process route involves a stage where the matrix is molten. Some discussion is also given to the thermomechanical processing of MMCs and of their properties.

This overview begins by considering the mature situation for polymer matrix composites (PMCs). After a further short section devoted to ceramic matrix composites (CMCs), the main text is devoted to the variety of routes available for processing metallic matrix composites (MMCs). These are divided into those where the main steps are performed in the solid state and those where the process route involves a stage where the matrix is molten. Some discussion is also given to the thermomechanical processing of MMCs and of their properties.

Toluene/water Pickering emulsions based on fibrous palygorskite clay particles were stabilized by increasing the solid particle concentration. The emulsion droplet size reached to a plateau at 2 wt.%, suggesting the development of a three dimensional network in the emulsion. This was supported by measuring the steady state shear stress-shear rate of emulsions at different concentrations of palygorskite particles. Oscillatory rheological measurements of storage modulus G′ and loss modulus G″ were then performed to verify that the emulsion system is strongly associated at concentrations greater than 2 wt.%, resulting in a viscoelastic film at the o/w interface. The role which palygorskite plays in emulsion stability by forming a three dimensional network is directly confirmed by observing the micro-morphology of palygorskite particles in the emulsions using polarizing optical microscope (POM) and transmission electron microscopy (TEM). Without any chemical modification, palygorskite fibers stabilized toluene/water Pickering emulsions over a wide range of pH (pH = 1.40 to 11.44). By adding HCl/NaOH, palygorskite clay-stabilized Pickering emulsions were successfully subjected to 5 emulsification-demulsification cycles, and all of the emulsions are stable for over 3 months in storage. Palygorskite has been demonstrated as an effective pH responsive emulsifier with long-term stability. The addition of NaCl leads to the aggregation and flocculation of the palygorskite particles, which increases the size of the emulsion droplets; however, stable toluene/water Pickering emulsions based on palygorskite clay can still be formed even at high NaCl concentrations.

A hybrid Mg composite filled with micro Al2O3 and nano TiO2 is manufactured through a blend press sinter powder metallurgy route. To appraise the significance of filler incorporation on the mechanical and corrosion strength, the composite is undergoing a series of characterizations. Initially the filler distribution was analyzed through electron microscopes. Static mechanical tests as per ASTM are conducted to measure the influence of fillers on the tensile and compression properties. The corrosion characteristics were studied by immersing the composites into the laboratory synthesized stimulated body fluid (SBF). Through the Tafel Polarization, the corroded surfaces are examined. The corrosion resistance of the composites exhibited a change that closely resembled that of pure magnesium. Based on the experimental findings, it appears that the composite being examined is well-suited for various biomedical applications, particularly in the field of dental implants.

Reconsolidation of thermally spray formed (plasma and high velocity oxyfuel spraying) hypereutectic Al-Si nanocomposites with multiwalled carbon nanotube (MWCNT) reinforcement was carried out by inert atmosphere sintering for prolonged time periods. The sintering treatment resulted in the removal of porosity and residual stress, and increase in size and volume fraction of primary Si particles in the Al-Si matrix. The morphology of multiwalled carbon nanotubes in sintered nanocomposites remained unchanged after sintering. The interfacial ultrathin product layer of silicon carbide between MWCNT reinforcement and Al-Si matrix was unaltered. Microhardness and elastic modulus of the sintered nanocomposites were influenced by combined effect of multiple factors, i.e. reduction in porosity, residual stress removal and MWCNT distribution. Overall improvement of microhardness and elastic modulus of the sintered nanocomposites was observed. The experimentally measured elastic modulus values were compared with theoretically estimated values using micromechanics models.

In this paper the physical and mechanical properties of Al nanocomposite reinforced with CNTs were investigated. Al powders with high purity and Carbon Nanotubes (CNTs) with different percentage were mixed by ball milling method and the composite was fabricated by cold pressing followed by sintering technique. The variation of density and hardness of composite with CNT content were investigated. The microstructure of composite was evaluated by SEM (Scanning Electron Microscope) and XRD (X -Ray Diffraction). The results show that the density and hardness increase with CNT percentage.